Sensors for detecting the presence of a given analyte in solution or in air are known. Such sensors may include mechanical-based sensors such as surface acoustical wave (SAW) devices, or non-mechanical-based sensors such as pH meters. These types of sensors require direct contact with a power supply coupled to electronics for detecting a response in the presence of a given analyte. Distributed wireless sensing systems are a potential alternative to these more conventional sensor systems.
Distributed wireless sensing systems or “sensor networks” are an emerging technology that promises unprecedented ability to monitor and manipulate the physical world via a spatially distributed network of small and inexpensive wireless sensor nodes that have the ability to self-organize into a well-connected network. A wide range of applications of sensor networks have been envisioned. While a practically unlimited range of applications of sensor networks may be imagined, current understanding of their design and management is far from complete.
The vision of massively distributed, autonomous, and untethered sensing systems to monitor spatial phenomena in complex, natural environments captures the grand scope and potential of sensor networks. However, one of the impediments to constructing large-scale distributed sensing systems is the network-centric focus of most research in the distributed wireless sensing arena. It has proven to be incredibly complicated to engineer self-configuring wireless networks, especially in applications where operating conditions are far from ideal. To date, wireless sensor networks involving on the order of 1000 nodes have been deployed with modest success. The vision of tens of thousands, millions, or billions of networked wireless sensors is far from being realized, and it may never materialize. Thus, the network-centric perspective, which is natural and appealing at first, may be a severe limiting factor in the development of large-scale autonomous distributed sensing systems.